diff --git a/mess_io/tests/test_read_rates.py b/mess_io/tests/test_read_rates.py
index 0b0656d..4be0812 100644
--- a/mess_io/tests/test_read_rates.py
+++ b/mess_io/tests/test_read_rates.py
@@ -288,7 +288,7 @@ def test__rxns_labels():
     )
 
     assert ref_rxns1 == mess_io.reader.rates.reactions(
-        KTP_OUT_STR, read_rev=True)
+        KTP_OUT_STR)
 
 
 def test__filter_ktp():